Financial Highlights (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Per Unit operating performance: [Abstract]
Net asset value at the beginning of the period (in dollars per unit)	$ 10.54		$ 9.69
Interest Income (in dollars per unit)	$ 0	[1]	$ 0	[1]
Expenses (in dollars per unit)	$ (0.21)		$ (0.2)
Realized/Unrealized Income (Loss) (in dollars per unit )	$ (1)	[2]	$ 0.73	[2]
Net Income (Loss) (in dollars per unit)	$ (1.21)	[3]	$ 0.53	[3]
Net asset value at the end of the period (in dollars per unit)	$ 9.33		$ 10.22
Ratios to average net assets: [Abstract]
Net Investment Loss (in hundredths)	(8.80%)	[4]	(8.10%)	[4]
Expenses before Incentive Fees (in hundredths)	8.80%	[4]	8.20%	[4]
Expenses after Incentive Fees (in hundredths)	8.80%	[4]	8.20%	[4]
Total return before incentive fees (in hundredths)	(11.50%)		5.50%
Total return after incentive fees (in hundredths)	(11.50%)		5.50%

[1] Amounts less than $0.005 per Unit.

[2] Realized/Unrealized Income (Loss) is a balancing amount necessary to reconcile the change in net asset value per Unit with the other per Unit information.

[3] Based on change in net asset value per Unit.

[4] Annualized (except for incentive fees if applicable).